Method for forming protective edge on easy opening container

ABSTRACT

A method for forming a protective edge on an easy opening container having an end closure including a chuck wall and a panel. The panel is formed with an annular folded band adjacent to the chuck wall and a weakening line is formed in the panel prior to completely folding the annular folded band.

United States Patent 119 I 1111 3,848,557 Hulk, Jr. a 1 Nov. 19, 1974METHOD FOR FORMING PROTECTIVE 3,698,590 10/1972 Cookson 220/54 1 0TAINER 3,055,539 9/1962 Pillnik 220/54 EDGE 0N EASY- P NG N 3,142,4127/1964 Blakeslee 220/54 [75] Inventor: Albert J- Ho k, Jr-, r o3,303,958 2/1967 Taylor 220/54 3,434,623 3/1969 Cookson 220/54 [73]Assgnee' 3,525,455 8/1970 Saunders.... 113/121 0 New York NY 3,696,9611'0/1972 Holk 220/54 22 Filed; 1v 1 1972 3,705,563 12/1972 Elser ll3/l2lC [21] Appl' 249326 Primary Examiner-C. W. Lanham Related US.Application Data Assistant Examiner-M. J. Keenan [60] Division of Ser.N0. 82,260, 001. 20, 1970, Pat. NO. f Agent Brow", Ramlk &

3,696,961, which is a continuation-in-part of Ser. No. Wlght 815,043,April 10, 1969, abandoned.

. [57] ABSTRACT [52] US. Cl. 113/121 C, 113/15 A v 51 1m. (:1 B2ld 51/26A P a Pmtectl"e edge 9" easy [58] Field of Search 113 21 C 15 A 15 Ropenmg contamer havlng an end closure mcluding a 3 /121 5 chuck wall anda panel. The panel is formed with an annular folded band adjacent to thechuck wall and a weakening line is formed in the panel prior-t0 com-[56] g giz g gif pletely folding the annular folded band.

2,017,460 10/1935 Hothersall 113/15 A 7 Claims, 12 Drawing FiguresMETHOD FOR FORMING PROTECTIVE EDGE ON EASY OPENING CONTAINER BACKGROUNDOF THE INVENTION This application is a division of U.S. Pat. applicationSer. No. 82,260 filed Oct. 20, 1970 said application Ser. No. 82,260,having granted as US. Pat. No. 3,696,961 on Oct. 10, 1972 which is acontinuation-inpart of US. Pat. application 815,043 filed Apr. 10, 1969,now abandoned.

The present invention relates to new and improved easy openingcontainers of the full panel opening type and more particularly to themethod of forming the same.

Full opening containers of the type to which the present inventionrelates include an end closure of which the end panel is formed with aweakening line located closely adjacent to the chuck wall. The weakeningline is formed by scoring and defines a removable panel section to whichthere is attached a pull tab. The pull tab is mounted so that uponinitial lifting thereof the nose of the tab penetrates the weakeningline to initiate the severance of the removable panel section from theend panel. Thereafter, the pull tab is pulled upwardly so that theremainder of the weakening line is ruptured and the removable panelportion separated from the remainder of the panel substantially in theform of a disc.

The opening thus formed in the end closure is bounded by a horizontalledge which terminates in a sharp raw edge caused by the severance ofthe removable panel portion therefrom. This sharp edge is somewhatobjectionable because it may cause injury by cutting the users hand orotherwise damage an article which may be inserted through the opening.

The edge on the removable portion is also sharp and is a hazard ifcarelessly discarded.

SUMMARY OF THE INVENTION By the present invention it is proposed toprovide a new and novel method for forming a full easy opening endclosure constructed with an annular fold panel having a folded edgelocated adjacent to a score line to guard against cutting along thesevered edge after removal of the removable panel portion.

In carrying out the method of constructing the end closure of thepresent invention, the annular fold panel is formed in stages and theweakening line is formed by scoring prior to the final fold step. Morespecifically the center panel of the end is formed with a side wall anda top wall. The side wall is partially folded and the panel is thenscored prior to completely folding the side wall.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspectiveview of an easy opening container incorporating the easy openingstructure of the present invention;

FIG. 2 is a top plan view of an easy opening container end closure witha portion of the panel being broken away to show underlying details ofthe annular fold band;

FIG. 3 is a fragmentary cross-sectional view of the container takengenerally along the lines 3-3 of FIG. 2 and showing the rupture of thepanel along the weakening line upon initial lifting of the pull tab;

2 FIGS. 4, 5, 6 and 7 are greatly enlarged fragmentary sectional viewsshowing sequentially how dies are employed to form the annular foldedportion and in FIG.

-6 showing the scoring die performing the weakening line prior to thefinal folding of the annular band by the final folding dies shown inFIG. 7;

FIG. 8 is a fragmentary cross-sectional view of another form of theinvention showing a plastic band disposed for separation with theremovable panel portion to provide a protective edge;

FIG. 9 is a fragmentary sectional view of a third embodiment of theinvention showing the folded annular panel formed on the removable panelportion;

FIG. 10 is a fragmentary cross-sectional view of a fourth embodiment ofthe invention showing annular fold panels formed on both the ledge andthe removal panel portion of the end closure; and

FIG. 11 is a fragmentary cross-sectional view of a fifth embodiment ofthe invention in which the fold panels are arranged somewhat differentlyfrom that shown in FIG. 10.

FIG. 12 is an enlarged cross-sectional view of still another embodimentof the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing inparticularly FIGS. 1 to 3, there is shown a sheet metal can 10 having atubular sheet metal body 11. Secured to the upper end of the metal body11 as by means of a double seam 13 is an easy opening end closure 12embodying the structure of the present invention. The lower end, notshown, of the body 11 is also provided with an end closure which isfixed thereto by a double seam.

The container body or can body 11 is formed from a metal blank which isformed into tubular configuration and its marginal edges bonded into alongitudinally extending side seam.

The upper end closure 12 may be formed from either tin plate or aluminumand includes a substantially horizontally extending central panel 14which extends over and covers the open end of the can body. The centralpanel is recessed within the body 11 so that the horizontal plane inwhich it lies is below the level of the lower edge of the double seam 13as shown in FIG. 3. At its periphery, the panel 14 is formed with achuck wall 16 which terminates in a horizontal flange 17 and a curledend 18. The horizontal flange l7 and curled end are double seamed intothe can body 11.

In accordance with the present invention as shown in FIG. 3, the centralpanel 14 is bent back upon itself outwardly away from the center andagain inwardly toward the center of the body 11 to form an annular fold19 adjacent to the chuck wall 16. The fold band 19 thus comprises twolayers 21 and 22 which are disposed below the panel 14. It is to beparticularly noted that the fold provides a turned smooth or hemmed edge23 facing along the interior of the container. Moreover, the panelportion 14 superimposed over the annular fold 19 is in close proximityto the chuck wall 17 and extends substantially planar toward the centerof the container body 11.

Formed in the panel portion 14 inwardly of the turned edge 23 is aweakening line 24 along which a removable panel portion 26 is separatedfrom the panel. The weakening line 24 is formed by means of scoring orthe like as more fully to be described hereinafter.

The weakening line 24 extends substantially continuously about andsubstantially concentric with the chuck wall 16. Disposed closelyadjacent to the primary weakening line may be a second concentric score25 which serves as an anti-fracture score to relieve the stresses in theweakening line.

Fixed to the removable panel portion 26 as by a rivet 27 which may beformed integral with the panel is a pull tab 28. The pull tab 28 issubstantially rigid along the length thereof and is formed at one endwith a ring or finger grip portion 29 and the other end with apenetrating nose 31. The nose 31 is disposed over the weakening line 24so as to penetrate the latter upon initial tilting upwardly of the pulltab 28. As shown, the pull tab 28 is tiltable about an attachment ear 32defined by a lance formed in the tab body. Upon tilting of the tab 28,the nose 31 is operative to initially sever the removable panel portionalong the weakening line 24 as shown in FIG. 3. It is to be noted thatthe weakening line 24 lies inwardly of and in close proximity to thesmooth hemmed edge 23 of the annular fold band 19 so that upondownwardly movement into the severing position there is no interferenceto resist the downwardly bending of the removable panel portion 26.

It is also to be noted that the annular bank 19 tends to render the areain which the score line is located more rigid by reducing theflexibility of the relatively thin guage metal from which the endclosure 12 is made. This increased rigidity at the score line aids infacilitating the removal of the removable panel portion 26 becausedownward bending of the panel is resisted and thereby minimizes theamount of force which must be applied on the pull tab 28 to initiallysever the weakening line 24. Moreover, upon upward pulling of the pulltab 28 to separate the remainder of the removable panel 26 from thepanel 14 along the weakening line 24, the annular fold band also servesto resist upward bending and facilitates the further separation.

Referring now to FIGS. 4, 5, 6 and 7 illustrating the stations forforming the end panel closure 12 of the present invention, in FIG. 4there is illustrated a first station for forming the same. The endclosure 12 is initially in the form of a disc and is positioned betweena lower male die set 36 and an upper female die set 37. The lower maledie set 36 includes a drawing punch 38 which is received within an axialrecess 39 of a draw die 41 of the upper female die set 37.Concentrically disposed about the .draw die 41 and the draw punch 38respectively is a lower flange forming member 42 and an upper flangeforming member 43. A forming punch 46 concentric with the upper flangeforming die 43 serves to form a downwardly depending lip 18a on theflange 17.

Initially, the flat disc is placed between the lower male die set 36 andthe upper female die set 37. As the upper and lower dies close together,the flange forming members 42 and 43 clamp the disc therebetween alongthe marginal edge portions thereof. Thereafter, the lip forming memberor punch 46 may descend to form the depending lip 18a to provide ashell. The female die 41 and draw punch 38 also close to form a hatsection 14a by which projects substantially above the flange 18. The hatshaped section 14a includes a horizontal top 140 which defines thecentral panel 14 and an upstanding flange 14b from which the annularfold band 19 is formed as more fully to be explained hereinafter.

The partially formed end unit as formed in FIG. 4 is then transferred toa second station as shown in FIG. 5 wherein a second set of dies 47 and48 including an upper die member 49 in the form of a hammer and a lowerdie member 51 in the form of an anvil. Disposed concentrically about thehammer 49 and anvil 51 is a pair of clamping rings .52 and 53 which whenclosed clamp the chuck wall 16 adjacent the lower end hereof.Thereafter, the hammer 49 strikes the horizontal web 14 and forces thelatter downwardly into engagement with the anvil 51. This causes thevertical wall 14b of the hat section to be reformed into a partiallyloosely folded condition, as shown, in the annular space providedbetween the hammer 49 and the upper ring clamp 52. It is to be notedthat the horizontal wall or panel 14c is then at substantially the samelevel as the flange 17.

Thereafter, the second stage end closure is transferred to a thirdstation as shown at which FIG. 6 the previous reformed hat section 14ais scored by a scoring die set including a scoring tool 54 and an anvil56. The scoring tool 54 includes a primary scoring rib 57 and ananti-fracture scoring rib 58. The anti-fracture scoring rib 58 serves toreduce the stresses on the primary score and may be omitted if the metalfrom which the end closure is made is not subject to fracture causingstresses on the primary score at the primary score 24. For supportingthe partially folded end closure, there is provided a nesting block 59which accommodates and supports the chuck wall 16 therein. It is to benoted that the end closure is supported so that no further bendingoccurs during the scoring operation when the anvil 56 and scoring tool54 are closed. The scoring of the end closure 12 in this manner permitsan accurate control of the residual thickness of the weakening line 24.This control of the thickness is not possible if the scoring is formedafter the annular bank 19 is formed because of the multiple thickness ofthe fold band structure 19. Obviously, it is not possible to alwaysmaintain a consistent and exact thickness of the fold layers 21 and 22and the overlying panel 14 when the end closures are made on a massproduction basis.

The partially formed and scored end closure 12 is thereafter transferredto the fourth station for final bending as shown in FIG. 7. The fourthstation includes an upper die set including a hammer 61 and a lower dieset providing a nesting block 62 into which the partially formed andscored end closure 12 is positioned. The lower nest block 62 includes anannular groove 63 in which the fold 19 is received when the upper andlower die set are closed. As shown, the hammer and nesting blocks 61 and62, respectively are shaped so that upon closing the layers 21 and 22are guided to be received within the groove 63.

In connection with the final folding operation, it is to be noted thatthe partially and loosely folded vertical web 14b, makes it possible tocomplete the fold 19 into the nesting block 62 without causing afracture along the score or weakening line 24. This is of significance,because in the absence of forming a partially folded side wall 14b tocomplete the fold at the second station it has been found impractical toform the weakening line 24 prior to forming the fold band 19.

Referring now to FIG 8, there is shown a modified arrangement of thestructure shown in FIGS. 1-3. The central panel 14 is formed with acircumferential downwardly depressed bead 33. The annular folded panelportion 19 is folded inboard and adjacent to the bead 33. The score line24 is located relative to the folded edge 23 in the same manner asdescribed heretofore in connection with FIGS. 1-3.

Attached to the underside of the removable pane portion 26 is aband 34of a pliable plastic such as plastisol. The plastisol band 34 is adheredby a suitable adhesive coating such as vinyl resin which may be appliedby spot coating on the removable panel portion 26.

The remainder of the underside of the panel 14 including the foldportion 23 may be coated with a coating non-adherent to the plastisol asfor example a thermo setting resin. The plastisol band 34 may be appliedby spin lining so that the fold edge 23 restricts the outward flow ofthe plastisol.

The removable panel portion 26 is separated from the panel similar tothe manner explained in connection with FIGS. 1-3. When the removablepanel portion 26 is separated, the portion of the band 34 laying in thepath of movement of the pull tab nose is initially also depresseddownwardly with the removable panel portion 26 past the folded edge 23.Thereafter, upon pulling of the pull tab 28 to complete the separationof the removable panel portion 26, the band 34 which is adhered to theremovable panel portion and not to the folded edge 223 is removedtherewith. The plastisol band 34 is of such width as to project radiallyoutwardly of the cut edge bounding the removable panel 26 upon removalthereby to protect the cut edge from contact by the user.

A third embodiment of the protective structure is shown in FIG. 9. Asshown, the panel 14 of the end closure 112 is formed with a fold band119 disposed a greater distance from the chuck wall 16 than the foldband 19 in the embodiment of FIGS. 1-3. This permits a score line 122 tobe formed in the annular space between the chuck wall 16 and an innerfolded edge 122. The score line 124 is located such that upon severanceby a pull tab 125 in the manner described in connection with FIGS. 1-3,the folded edge projects outwardly of the severed edge of the sufficientamount to prevent free contact therewith. In this manner, the cut edgeof the removable panel portion 126 is protected.

If desired, the edge on the ledge 128 may be protected by a plastisolband 134. The plastisol band 134 is adhered to the underside of theledge 118 as by a spot coating by a band of an adhesive such as a vinylresin coating. The vinyl resin coating may be applied on an non-adherentcoating such as a theremo-setting resin coating covering the undersideof the panel. The portion of band overlying the thermo-setting coatingis not adherent thereto so that upon severance of the removable panelportion 126, the band 134 remains adhered to and projects outwardly ofthe cut edge of the ledge 128.

Referring now to FIG. 10, there is shown a fourth embodiment of theinvention. The end closure 212 includes a central panel 214 which isformed with a pair of radially spaced annular fold panels 215 and 216.The panel 215 includes fold layers 217, 218 and 219. The fold layer 218is common to the fold panel 216 which also includes fold layers 2'20 and221. The fold layers 217 and 218 are connected by a folded edge 222 andthe fold layers 220 and 221 by a folded edge 223. Provided on the foldlayer 219 is a score line 224. The score line 224 is located so thatupon separation of the removable panel portion 225 defined by the scoreline 224, the raw or cut edges contiguous to the fold layers areprotected by the folded edges 222 and 223, respec tively.

For removing the removable panel portion 225, there is provided a pulltab 227. The pull tab 227 is mounted in substantially the same manner asthe pull tab of FIGS. 1-3. The pull tab 227 includes a downwardlyprojected nose 228 which overlies the score line 224. Upon tilting ofthe pull tab 227, the pull tab nose 228 severs the score line 224 andthe folded panel 228 is depressed downwardly past the folded edge 224.Thereafter, the pull tab 227 is pulled upwardly so that the removablepanel 225 is completely separated. In this matter, the fold panel 216 isremoved with the removable panel portion and fold panel 215 remainsattached to the container. The cut edge overlying the folded edge 224 isprotected thereby and the folded edge 223 protects the cut edge on theremovable panel portion 225.

Referring now to FIG. 11, there is shown another embodiment of theinvention differing from the embodiment of FIG. 10 by the fact thatannular folded panels 315 and 316 are folded toward the interior of thecontainer rather than the exterior. The folded panel 315 includes anouter layer 317, an intermediate layer 318 and a bottom layer 319. Thebottom layer 319 forms the upper layer of the folded panel 316.Underlying the layer 319 are fold layers 320 and 321. The fold layers317 and 318 are folded along a folded edge 322 while the fold layers 320and 321 are folded along the folded edge 323.

A score line 327 is formed in the panel 319 between the fold edges 322and 323. The score line 323 is severed by tilting of the pull tab 324 sothat a nose 325 engages the weakening line 327 so that the portion ofthe fold panel 316 adjacent thereto is depressed downwardly into thecontainer body. Thereafter, upward pulling of the pull tab 324 causesthe remainder of the removable panel portion 326 to be separated fromthe end closure.

It is to be noted that upon separation of the removable panel portionthat the folded edge 322 protects the cut edge of the score lineremaining on the end closure, while the folded edge 323 protects the cutedge on the removable panel portion 326.

Referring now to FIG. 12 there is shown a still further embodiment ofthe invention in which an end closure 410 has fold layers 411 and 412underlying a marginal panel 413 extending from the chuck wall 414. Thefold layers 411 and 412 define an annular fold panel 415. Connecting thefold layers 411 and 412 is a folded edge 416. Disposed closely to thefolded edge 416 on the panel portion 413 is a score line 417 whichdefines a removable panel portion 418. Mounted on the removable panelportion similar to the manner described in connection with the priorembodiments is a pull tab 419 having a nose 421. Upon tilting of thepull tab 419 the score line is severed and upward pulling thereaftercompletely separates the removable panel. When the removable panelportion 418 is completely separated, the folded edge 416 of the foldpanel 419 protects the cut edge bounding the portion 418.

If desired the cut edge of the ledge may be protected by aplastisol band(not shown) applied to the underside of the end closure so as to remainadhered to the end after removal of the removable panel portion.

What is claimed is:

1. A method of forming an easy opening end closure comprising forming ashell having an upstanding chuck wall about a panel, drawing a majorportion of said panel into a substantially hat shaped section having atransverse wall and a side wall, partially folding said side wall,scoring said panel to form a weakening line at least after saidpartially folding of said side wall has been initiated, and thereaftercompletely folding said side wall to form a double thickness annularfolded band about said transverse wall.

2. The method as defined in claim 1 wherein said annular folded band isformed to underlie said panel.

3. The method as defined in claim 1 wherein said annular folded band isformed to overlie said panel.

4. The method as defined in claim 1 wherein said weakening line isformed in said panel so as to be disposed along the outer edge of saidannular folded band.

5. The method as defined in claim 1 wherein said weakening line isformed along the inner edge of said annular folded band.

6. A method of forming an easy opening end closure from a shell having apanel, forming said panel into a substantially hat shaped sectionincluding a transverse wall and a side wall, displacing the oppositeends of said side wall relatively to each other so that the end remotefrom said transverse wall of said side wall is disposed inwardly of themarginal edge of said transverse wall, pressing said side wall intotight engagement with said panel to form an annular folded band, andscoring said panel along a line adjacent a folded edge of said foldedannular band at least subsequent to the initiation of the displacing ofthe opposite ends of said side wall relative to each other and prior topressing said side wall into tight engagement with said panel.

7. A method of making an easy opening container wall comprising:

providing a piece of sheet material including axially offset sectionsjoined by a connecting section; partially deforming said connectingsection to form a prefold having a plurality of angularly transaxiallyextending portions including end portions and a connecting incliningportion, then scoring at least one of said axially offset sections inthe region of the respective end portion, then closing said prefold toprovide a fold contiguous to said scoring to protect the user againstinjury from the sharp edge upon rupture of the sheet material along theline of the score.

1. A method of forming an easy opening end closure comprising forming ashell having an upstanding chuck wall about a panel, drawing a majorportion of said panel into a substantially hat shaped section having atransverse wall and a side wall, partially folding said side wall,scoring said panel to form a weakening line at least after saidpartially folding of said side wall has been initiated, and thereaftercompletely folding said side wall to form a double thickness annularfolded band about said transverse wall.
 2. The method as defined inclaim 1 wherein said annular folded band is formed to underlie saidpanel.
 3. The method as defined in claim 1 wherein said annular foldedband is formed to overlie said panel.
 4. The method as defined in claim1 wherein said weakening line is formed in said panel so as to bedisposed along the outer edge of said annular folded band.
 5. The methodas defined in claim 1 wherein said weakening line is formed along theinner edge of said annular folded band.
 6. A method of forming an easyopening end closure from a shell having a panel, forming said panel intoa substantially hat shaped section including a transverse wall and aside wall, displacing the opposite ends of said side wall relatively toeach other so that the end remote from said transverse wall of said sidewall is disposed inwardly of the marginal edge of said transverse wall,pressing said side wall into tight engagement with said panel to form anannular folded band, and scoring said panel along a line adjacent afolded edge of said folded annular band at least subsequent to theinitiation of the displacing of the opposite ends of said side wallrelative to each other and prior to pressing said side wall into tightengagement with said panel.
 7. A method of making an easy openingcontainer wall comprising: providing a piece of sheet material includingaxially offset sections joined by a connecting section; partiallydeforming said connecting section to form a prefold having a pluralityof angularly transaxially extending portions including end portions anda connecting inclining portion, then scoring at least one of saidaxially offset sections in the region of the respective end portion,then closing said prefold to provide a fold contiguous to said scoringto protect the user against injury from the sharp edge upon rupture ofthe sheet material along the line of the score.